Just one little question on the frequency band of the series RLC filter

AI Thread Summary
The discussion focuses on the relationship between resistance (R) and the width of the frequency band rejected in a series RLC filter. The user derives the equation for the bandwidth, Δω, showing that it equals R/L, leading to Δf = R/(2πL). However, the textbook states that Δω = R/(2L), which causes confusion regarding the definition of Δω as the frequency difference at half the maximum power. The user seeks clarification on whether their calculations are incorrect or if the textbook's explanation is misleading. The inquiry highlights the importance of understanding the definitions and relationships in RLC circuits for accurate analysis.
Lisa...
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Hey! I really need to find out how the width of the frequency band rejected depends on the resistance R of the following circuit:

http://img418.imageshack.us/img418/8168/rlc2wf.gif

I've done the following:
Q= \frac{\omega_0}{\Delta \omega}

so

\Delta \omega = \frac{\omega_0}{Q}

with

Q= \frac{\omega_0 L}{R}

Substitution gives:

\Delta \omega = \frac{\omega_0}{\frac{\omega_0 L}{R}}

=\frac{R}{L}


\Delta f= \frac{\Delta \omega}{2 \pi}

= \frac{\frac{R}{L}}{2 \pi}

= \frac{R}{2 \pi L}


Though my textbook says that

\Delta \omega = \frac{R}{2L}

... and it defines the delta omega as the frequency difference between the two points on the average power vs generator frequency curve where the power is half its maximum value...

So am I wrong or is the textbook's answer just confusing?
 
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